225mm crank arms for huge person?
10-19-18, 12:05 PM
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225mm crank arms for huge person?
I'm getting a new custom road bike designed, and the shop wrote yesterday and said they want to put 225mm crank arms on it. I've used 175s for the past 20 years. My first thought was "hey, more leverage, I can go faster!" My second thought was "too much torque, I'll destroy them!"
Anyone here ever tried them? Do they help you go faster? Or is it more comfortable?
For reference, I weigh 350 pounds and am 6 feet 9 inches tall.
Anyone here ever tried them? Do they help you go faster? Or is it more comfortable?
For reference, I weigh 350 pounds and am 6 feet 9 inches tall.
10-19-18, 04:03 PM
#2
Senior Member
Interesting choice and very long! Have they given you reasoning for the length?
Crank length is a black art. Because people that would suit longer cranks are so small in number, there just isn’t much research on it. There is reasoning for better muscle recruitment, but it’s all very subjective. I had my own road bike fit while I was being fitted up for a custom track frame. The interesting outcome from that was no longer than 180 on the road and 175 for track. Interesting because I’m 6’5” with long legs and arms and longer length was an option.
As for speed/gearing, you have to remember that cranks are just a part of the gearing combination or gain ratio. Longer cranks reduce the gearing. You’ll find hills a lot easier (the cranks alone are a 28.6% change in gearing) but flats will suffer. Your cadence will reduce as you foot speed increases.
The outcome will be interesting and I hope your fitter is knowledgeable enough that it’s the right choice for you
Crank length is a black art. Because people that would suit longer cranks are so small in number, there just isn’t much research on it. There is reasoning for better muscle recruitment, but it’s all very subjective. I had my own road bike fit while I was being fitted up for a custom track frame. The interesting outcome from that was no longer than 180 on the road and 175 for track. Interesting because I’m 6’5” with long legs and arms and longer length was an option.
As for speed/gearing, you have to remember that cranks are just a part of the gearing combination or gain ratio. Longer cranks reduce the gearing. You’ll find hills a lot easier (the cranks alone are a 28.6% change in gearing) but flats will suffer. Your cadence will reduce as you foot speed increases.
The outcome will be interesting and I hope your fitter is knowledgeable enough that it’s the right choice for you
10-19-18, 04:55 PM
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I can think of foot/tire clearance issues when turning the bars and also foot/ground issues when leaning the bike. Pedal strikes are a B***** and often will high side you faster then your can scream Mama.
I think 180mm was the magic math back in the days. Added almost 2" of leverage (225) is allot of stress on the bottom bracket and all the tubes that connect to it.
There are few things you can't create on a custom bike, new wheel sizes and crank arms. Everything else is just tubes and angles
I think 180mm was the magic math back in the days. Added almost 2" of leverage (225) is allot of stress on the bottom bracket and all the tubes that connect to it.
There are few things you can't create on a custom bike, new wheel sizes and crank arms. Everything else is just tubes and angles
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10-19-18, 05:27 PM
#4
Banned
I'll defer To Lennard Zinn Frame builder for tall people and Column Writer for Velo News ,
who offers a long arm crank sets .
I have some M730 XT 180.s but I'm a Plodding Bike tourist. with a slow cadence and rate of speed
and gear down as needed to not push too hard.. with my loaded bike ..
That I just used it on a grocery run ..
....
who offers a long arm crank sets .
I have some M730 XT 180.s but I'm a Plodding Bike tourist. with a slow cadence and rate of speed
and gear down as needed to not push too hard.. with my loaded bike ..
That I just used it on a grocery run ..
....
10-24-18, 09:13 PM
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Pedal strike when cornering?
5cm extra can easily cause problems
I'm getting a new custom road bike designed, and the shop wrote yesterday and said they want to put 225mm crank arms on it. I've used 175s for the past 20 years. My first thought was "hey, more leverage, I can go faster!" My second thought was "too much torque, I'll destroy them!"
Anyone here ever tried them? Do they help you go faster? Or is it more comfortable?
For reference, I weigh 350 pounds and am 6 feet 9 inches tall.
Anyone here ever tried them? Do they help you go faster? Or is it more comfortable?
For reference, I weigh 350 pounds and am 6 feet 9 inches tall.
10-24-18, 09:24 PM
#6
Senior Member
Don't know where you'd find such a thing off the shelf-- must be one of a kind. Plenty of taller guys going to smaller cranks for improved RPMs and keeping knees from hitting their chest when pedaling in an aerodynamic position. Good thing about long cranks is the seat doesn't have to be as high but, I'd be worried about toe-overlap and hitting the pedal on the ground when leaning the bike (forget about toe clips).
10-24-18, 09:29 PM
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This bike comes with 200’s. There are not many off the rack bikes like this.
https://khsbicycles.com/bikes/2014-k.../flite-747-14/
Regular crank arms can be drilled shorter or longer a little bit but 225 is two inches longer, so it’s got to be custom, hung on a custom frame
https://khsbicycles.com/bikes/2014-k.../flite-747-14/
Regular crank arms can be drilled shorter or longer a little bit but 225 is two inches longer, so it’s got to be custom, hung on a custom frame
10-24-18, 09:37 PM
#8
Non omnino gravis
220mm cranks on that DirtySixer. Looks like no worries of pedal strike. They also use 1.5" straight steerer tubes. Bikes properly built for big heavy riders will take these things into consideration. If the builder is recommending 225 cranks, there's probably a reason.
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10-24-18, 11:25 PM
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Let’s hear from someone who has actually used proportionally sized cranks. There is way too much misinformation out there in the public consciousness. I am just a little guy: 6’6” 220 pounds. I ride 200mm cranks, and it was the single biggest revelation I have had on a bike.
- Do they hit the ground? No. Like many tall people, I ride custom frames. The bottom bracket is simply raised to compensate.
- Do they lower my cadence? Yes, to a normal range. On 180mm cranks I had to spin my brains out to get power down. That isn’t necessary any longer. Mice walk with a high cadence. Giraffes with a low cadence. This isn’t a problem that needs correcting.
- Can I get aero? Absolutely. They are proportional, not long. I had a lot of room between knee and chest, now I have a little less. Do average size men get aero by using 145mm cranks? No. They could not produce power.
- Do they cause my foot to touch the front wheel? Not even close. I have a big bike!
- Do they cause knee pain? No, they solved it. As a large person, I produce, and need more power. Trying to put down power with small cranks means more force and higher cadence. That results in knee strain. I always had knee pain, until I got proportional length cranks. If a short person gets knee pain from long cranks, that means nothing to a tall person. I dont know why people always bring this up.
- Do they slow me down? I immediately went out and started setting personal bests. Some as much as 20% better.
- Do they hurt my endurance? On the contrary. I come back from long rides tired, but my legs feel great, and I can lay down power deep into a ride and sustain a good pace. With 180mm or 175mm cranks, my legs would be trashed very early in the ride, so I slowed way down.
- Does it break things? I have broken things, but not since using longer cranks. Big people need to choose parts wisely.
- Where do I buy longer (or shorter) cranks?
- IRD super long cranks, 200mm, $150 at Universal Cycles.
- Zinn Cycles has a number of custom products, from several suppliers.
- High Sierra makes beautiful aluminum and carbon custom cranks. Also for special needs. They can do a bike fit more in depth than most.
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10-25-18, 11:24 AM
#10
Senior Member
In these ranges, 'correcting' requires nothing more selecting the desired cassette size. My understandingn is that, among triathletes, for example, you're pretty much talking about sub-150s nowadays to be thought of as actually going to a, "shorter" crank. Mouse vs. giraffe examples don't work because, the larger the crank the higher the foot speed at any given RPM so going to a larger crank could just as easily be likened to riding like a rat.
10-25-18, 12:55 PM
#11
SuperGimp
Let’s hear from someone who has actually used proportionally sized cranks. There is way too much misinformation out there in the public consciousness. I am just a little guy: 6’6” 220 pounds. I ride 200mm cranks, and it was the single biggest revelation I have had on a bike.
10-25-18, 08:00 PM
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The point is, the longer and heavier the legs, the lower the cadence you would expect. If I were walking next to you, I would have the same foot speed, but a lower cadence. If I had the same foot speed on my long cranks, I would have a lower cadence. That makes sense because I am taller than average. So when someone warns, as someone always does, that longer cranks will lower your cadence, I say what is your point, a taller person should have a lower cadence.
Of course that is all relative. My new cranks are 10% longer, so I upped the gearing 10%, on Zinn’s theory of constant foot speed. That is 1 cog in the rear, or 4 teeth up front. As good a formula as any. Over time I discovered the most comfortable cadence was a little lower than that prediction. I can spin the same cadence as before, regularly ranging up to 220, but for general riding, your body has a way of finding what is most efficient.
The sad truth is, most tall people are far more likely to drop the sport with discomfort than to try longer cranks, simply because it is easier to perpetuate myths than it is to supply cranks in a meaningful range of sizes.
10-25-18, 08:35 PM
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I'm not a clyde nor especially tall. Long limbed 150 pounder. 6'1/2" before age started shorteining me, I had always ridden 170 crank s or shorter (on a very low bottom bracket fix gear). I got talked into buying a racing bike with 175s (and several other big changes). Night and day! First ride, I rode my 45 mile loop easy. (Mid-season as a racer - didn't want to harm my knees or anything else with the change.) Matched my best ever time. 3 days later 2 more minutes fell off. And I just kept going faster. Later that season I rode a race way beyond what I thought this body could ever do.
This to say - fit matters! Big time! The idea that you should be riding crank anywhere near me at 77% of your dimensions is ridiculous. Your proposed 225s are just my cranks scaled up to our difference in size. (My calculator came up with 226. I don't argue single millimeters.) Yes, all the rest of the bike will have to be designed with those big cranks in mind. Yes, this bike will look quite unusual, especially when you are off it. But if the builder does his work, it will look right when you are on it, even if it looks very different. And the reality is that 225s are probably not your ideal crank, that with enough riding, you will find you want 5 or 10 mm larger or smaller. But 225 will get you in the ballpark. Nothing in most any catalogue will get you even close.
Go for it! You only live once. Don't spend that life riding bikes that don't fit.
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This to say - fit matters! Big time! The idea that you should be riding crank anywhere near me at 77% of your dimensions is ridiculous. Your proposed 225s are just my cranks scaled up to our difference in size. (My calculator came up with 226. I don't argue single millimeters.) Yes, all the rest of the bike will have to be designed with those big cranks in mind. Yes, this bike will look quite unusual, especially when you are off it. But if the builder does his work, it will look right when you are on it, even if it looks very different. And the reality is that 225s are probably not your ideal crank, that with enough riding, you will find you want 5 or 10 mm larger or smaller. But 225 will get you in the ballpark. Nothing in most any catalogue will get you even close.
Go for it! You only live once. Don't spend that life riding bikes that don't fit.
Ben
10-25-18, 08:53 PM
#14
Senior Member
It's all anecdotal at this point but, 6'6 Johan Vansummeren, tallest dude in the TDF, rides a 58c Cervélo R5 with 180mm cranks and oval Q Rings.
10-26-18, 10:27 AM
#16
Senior Member
Interesting article here (see below). If you had to generalize, if uncertain and are willinging to entertain a healthy skepticism when it comes to commonly accepted crank lengths relative to body size, you'd probably want to consider shorter not longer, e.g.,
Let’s look at an example. This year’s IRONMAN World Champion, Jan Frodeno has a saddle height of 860mm and rides a crank length of 172.5mm. This seems pretty normal and doesn’t turn any heads. We could even say that Jan doesn’t use a short crank. However, if we took the ratio of his saddle height:crank length and applied it to a smaller athlete such as Rachel Joyce or Mirinda Carfrae (both have a saddle heights around 670mm and ride 165mm crank lengths), they would need to move down to approximately 135mm crank length to maintain Jan’s ratio. If we reversed this and wanted Jan to replicate Rachel and Mirinda’s ratio, Jan would need to bump his crank length up to approximately 210mm.
A less extreme example, take an average person with a saddle height of 750 mm and put them on a 170mm crank. Keeping a similar ratio would put Rachel and Mirinda on a 150mm crank and Jan up to a 195mm crank length. You can break this down however you want…maybe you use limb segment length? What I’m trying to show is that there are big variances in rider size but only a small difference between “acceptable” crank lengths to choose from. And, when you look at crank length from a rider proportion standpoint, some athletes are using crank lengths much shorter than others without a loss in performance.
Let’s look at an example. This year’s IRONMAN World Champion, Jan Frodeno has a saddle height of 860mm and rides a crank length of 172.5mm. This seems pretty normal and doesn’t turn any heads. We could even say that Jan doesn’t use a short crank. However, if we took the ratio of his saddle height:crank length and applied it to a smaller athlete such as Rachel Joyce or Mirinda Carfrae (both have a saddle heights around 670mm and ride 165mm crank lengths), they would need to move down to approximately 135mm crank length to maintain Jan’s ratio. If we reversed this and wanted Jan to replicate Rachel and Mirinda’s ratio, Jan would need to bump his crank length up to approximately 210mm.
A less extreme example, take an average person with a saddle height of 750 mm and put them on a 170mm crank. Keeping a similar ratio would put Rachel and Mirinda on a 150mm crank and Jan up to a 195mm crank length. You can break this down however you want…maybe you use limb segment length? What I’m trying to show is that there are big variances in rider size but only a small difference between “acceptable” crank lengths to choose from. And, when you look at crank length from a rider proportion standpoint, some athletes are using crank lengths much shorter than others without a loss in performance.
10-26-18, 12:07 PM
#17
Non omnino gravis
I don't want to be the one to point this out, but the difference between a 6'3" guy and a 6'9" is significant. After all, I'm barely 6'2" (anymore) and my saddle height (with 175mm cranks) is a scant 7mm lower than Frodeno's. If I were 7" taller, I wouldn't be at all surprised if my fit called for cranks an inch longer. Or more.
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10-26-18, 08:37 PM
#18
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I don't want to be the one to point this out, but the difference between a 6'3" guy and a 6'9" is significant. After all, I'm barely 6'2" (anymore) and my saddle height (with 175mm cranks) is a scant 7mm lower than Frodeno's. If I were 7" taller, I wouldn't be at all surprised if my fit called for cranks an inch longer. Or more.
Your legs probably aren't much different in length from when your were 6'3 so, based on Frodeno's example, you could be spinning and perhaps preferring... 169s.
Last edited by McBTC; 10-26-18 at 09:18 PM.
10-26-18, 10:48 PM
#19
Non omnino gravis
Not to point out the obvious, but I'm guessing the OP's bike is gonna fit him just a little bit different than Frodeno's fits him.
There are as many schools of thought on crank length as there are different crank lengths. I'm approaching 40,000 miles on 175 cranks. I can't imagine a different crank length making much of a difference to me, so I've no desire to investigate.
I just cannot at all see how it's any more or less valid to recommend the OP to 180, or 225, or whatever length. There is apparently no right answer.
There are as many schools of thought on crank length as there are different crank lengths. I'm approaching 40,000 miles on 175 cranks. I can't imagine a different crank length making much of a difference to me, so I've no desire to investigate.
I just cannot at all see how it's any more or less valid to recommend the OP to 180, or 225, or whatever length. There is apparently no right answer.
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10-27-18, 12:59 AM
#20
Senior Member
At 1:04 in the below vid there is discussion on crank length. The fact that makes this issue so complicated is that a number of studies have found consistent power production across a fairly wide range of crank lengths. It’s not just about physiology, otherwise there should be a discernible peak in the data and there isn’t. IMO longer cranks likely recruit more muscles and increase ROM which from a health and general well-being perspective should be a benefit. But for going fast, shorter is better.
10-27-18, 09:25 AM
#21
Senior Member
At 1:04 in the below vid there is discussion on crank length. The fact that makes this issue so complicated is that a number of studies have found consistent power production across a fairly wide range of crank lengths. It’s not just about physiology, otherwise there should be a discernible peak in the data and there isn’t. IMO longer cranks likely recruit more muscles and increase ROM which from a health and general well-being perspective should be a benefit. But for going fast, shorter is better.
https://youtu.be/5i9DtIFi9pM
https://youtu.be/5i9DtIFi9pM
https://www.stevehoggbikefitting.com...gth-which-one/
10-27-18, 12:14 PM
#22
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Leonard Zinn did several studies, as much as he could afford himself, trying to show a performance benifit to proportional size cranks for tall riders. He could never tease anything out of it. Can average size men perform equally on 145mm cranks? Most studies say yes, at least on measured intervals. Same on 220mm cranks. Tall riders seldom make up a statistically significant portion of such studies to demonstrate a shift in the bell curve relative to size anyway.
Pro riders are restricted by team equipment and UCI rules. So non racers should not read too much into these anecdotal examples. Miguel Endurain Rode 180mm cranks, but he hid this fact out of embarrassment against the cycling culture of the times. This still persists. Ignore it when someone says dont try.
To me that says, if you can afford to, try something proportional, relative to your discipline. Don’t expect big gains, like I did. But it may feel better, more comfortable, making your rides more enjoyable, and it most likely wont hurt. It is extremely rare for someone who tries it to regret it. But they often do want to try even longer, because if some is good, maybe more is even better.
Only you can say what works for you, and can only rule out what you personally have tried.
Pro riders are restricted by team equipment and UCI rules. So non racers should not read too much into these anecdotal examples. Miguel Endurain Rode 180mm cranks, but he hid this fact out of embarrassment against the cycling culture of the times. This still persists. Ignore it when someone says dont try.
To me that says, if you can afford to, try something proportional, relative to your discipline. Don’t expect big gains, like I did. But it may feel better, more comfortable, making your rides more enjoyable, and it most likely wont hurt. It is extremely rare for someone who tries it to regret it. But they often do want to try even longer, because if some is good, maybe more is even better.
Only you can say what works for you, and can only rule out what you personally have tried.
10-27-18, 06:13 PM
#23
Senior Member
True, true... it's all very personal but for whatever it's worth, if you're no longer in your 20s and decide to start training to use the biggest performance benefit you'll see in cycling -- aerobars -- I suggest either tiptoeing in very, very slowly or you may regret it for many months. That said... drop down in crank length before assuming that aero position and my experience has been that things will go a lot better for 'ya.
10-28-18, 09:11 PM
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Hi guys!
Wow, I took a few days off from checking the thread, and now there's all this interesting advice. The shop called again to ask if I wanted more info before committing, and we talked about cranks, and the fitter said that it was actually 210s that he was recommending on this custom frame that he's proposing to build. And, he said not to get too worked up over that number -- you marry the frame, but date the parts, in his words. So I probably will go for the 210s and see how that works.
Wow, I took a few days off from checking the thread, and now there's all this interesting advice. The shop called again to ask if I wanted more info before committing, and we talked about cranks, and the fitter said that it was actually 210s that he was recommending on this custom frame that he's proposing to build. And, he said not to get too worked up over that number -- you marry the frame, but date the parts, in his words. So I probably will go for the 210s and see how that works.
10-29-18, 11:58 AM
#25
Uber Goober
"you marry the frame, but date the parts"
I like that quote!
I'll point out that a part of it is that whatever you're used to feels right, and whatever you're not used to feels not-so-right.
Also, I know a number of people that ride a LOT, and some of them can just hop on anything and some of them have to have everything just-so or they hurt, and some of them are forever changing what the "just-so" is. So it makes it hard to predict how things will work out for you from what works for me.
I think my bikes all have 175's, except for India-made bike that's a copy of some of the Raleigh frames, and it is noticeably longer cranks. It doesn't feel bad, but feels distinctly different when you get on.
I'm around 6'-1" and I know people quite a bit shorter that use 175's or 172.5's, so not everyone uses proportional cranks.
Also, I understand that to some extent, triathlon racers optimize their biking to help their total time- not just their biking time. So I've read that supposedly the tri-bike position helps you in the running. The point being, that triathlon wisdom might not be the optimum choice for bicycle-only use.
I like that quote!
I'll point out that a part of it is that whatever you're used to feels right, and whatever you're not used to feels not-so-right.
Also, I know a number of people that ride a LOT, and some of them can just hop on anything and some of them have to have everything just-so or they hurt, and some of them are forever changing what the "just-so" is. So it makes it hard to predict how things will work out for you from what works for me.
I think my bikes all have 175's, except for India-made bike that's a copy of some of the Raleigh frames, and it is noticeably longer cranks. It doesn't feel bad, but feels distinctly different when you get on.
I'm around 6'-1" and I know people quite a bit shorter that use 175's or 172.5's, so not everyone uses proportional cranks.
Also, I understand that to some extent, triathlon racers optimize their biking to help their total time- not just their biking time. So I've read that supposedly the tri-bike position helps you in the running. The point being, that triathlon wisdom might not be the optimum choice for bicycle-only use.
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